Exemplary embodiments generally relate to correlated double sampling technologies, and more particularly to correlated double sampling circuits and image sensors including correlated double sampling circuits.
Charge coupled device (CCD) image sensors and complementary metal oxide semiconductor (CMOS) image sensors have been used as devices for capturing images. In general, analog pixel signals output from pixel arrays of the CMOS image sensors may have variations due to differences between intrinsic characteristics of pixels, such as fixed pattern noise (FPN). To reduce the FPN, a correlated double sampling (CDS) technology may be used to operate the CMOS image sensors. Recently, various schemes have been proposed to reduce random noise, as well as the FPN.